Message exchange services for mobile phones are extremely popular in Europe. According to statistical data, over 20 billion messages were sent in 2003 in the United Kingdom alone. The U.S. market for mobile phone message exchange is also rapidly growing.
One exemplary mobile phone message exchange service is SMS (Short Message Service). SMS provides for sending messages of up to 160 characters (224 characters if using a 5-bit mode) to mobile phones that use Global System for Mobile communication. SMS is similar to paging. However, SMS messages do not require the mobile phone to be active and within range and will be held for a number of days until the phone becomes active and within range. SMS messages are transmitted within the same cell or to anyone with roaming service capability. They can also be sent to digital phones from a web site equipped with PC Link or from one digital phone to another. Typical uses of SMS include notifying a mobile phone owner of a voicemail message, notifying a salesperson of an inquiry and contact to call, notifying a doctor of a patient with an emergency problem, notifying a service person of the time and place of their next call, and notifying a driver of the address of the next pickup.
Typically, wireless operators use a short message peer to peer (SMPP) protocol to allow third parties send and receive SMS messages on the wireless network. The SMPP protocol is an open, industry standard messaging protocol designed to simplify integration of data applications with wireless mobile networks.